Serving Etiquette
As the server, you have responsibility to maintain certain etiquette during a match. These are not definitive rules, but general things expected of you as the server:
Retrieve the shuttle: First, retrieve the shuttle.
Call out the score: Then call out your score, then your opponent’s score. For example, if you have 13 points and your opponent has 11, call out: “13-11.” Not only does this verify the score, but it also works as a signal that you are ready to serve.
Check that your opponent is ready: As a courtesy, always check to see if your opponent is ready to receive service. Your opponent should assume a ready stance or make eye contact to indicate readiness. After you see that your opponent is ready, then you can focus on your serve.
Thank your opponent: While the opponents should return the shuttle to you, they certainly don’t need to. Be sure to thank your opponents whenever they retrieve the shuttle for you.
Read more at: http://badminton.isport.com/badminton-guides/rules-etiquette-for-competitive-badminton